Intravenous Iron for Perioperative Anaemia in Colorectal Cancer Surgery: A Nested Cohort Analysis

Background/Objectives: Iron deficiency anaemia (IDA) is a common complication in patients with colorectal cancer presenting for surgery. Perioperative IDA is associated with increased post-operative mortality and morbidity. The impact on clinical outcomes for the active management of anaemia before surgery, with treatments such as intravenous (IV) iron, is uncertain. Methods: We performed a single-centre nested cohort study, analysing prospectively collected data from patients with colorectal cancer who were treated with IV iron prior to elective major abdominal surgery. Cox proportional hazard models were used to quantify the effect of anaemia treatment on length of stay. Other outcomes, including transfusion rates, were estimated using logistic regression analyses. Models were adjusted for age, sex, comorbidities and surgical details. Results: The length of stay was longer for patients with untreated anaemia compared to patients without anaemia (adjusted hazard ratio, HR 0.66 [95% confidence interval, CI 0.45, 0.95]). For patients with anaemia, the length of stay was shorter in those treated when compared to those not treated (adjusted HR 0.59 [95% CI 0.45, 0.78]). Patients with untreated anaemia had higher transfusion rates than patients with treated anaemia (adjusted odds ratio, OR 0.35 [95% CI 0.18, 0.66]) and non-anaemic patients (adjusted odds ratio, OR 0.20 [95% CI 0.07, 0.55]). Conclusions: This study suggests that treating iron deficiency anaemia with IV iron pre-operatively reduces length of stay and transfusion rates in colorectal cancer patients.